Turbo my is300 or go with 1jz swap - Page 2 - Lexus IS Forum
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post #16 of 18 (permalink) Old 04-19-2018, 04:39 PM
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Hahahahaha. The abysmal fuel economy is why I have a dd and never used the damn thing. It mostly sits in pieces in the garage. Gotta understand though, they are so cheap nowadays that it's a kids market. Welcome to the new forums :s

Originally Posted by Squareback View Post
1-8-7 on the undercova i-s-3-hundgy
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post #17 of 18 (permalink) Old 04-19-2018, 09:07 PM
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Originally Posted by zukikat View Post
From the Lexus offerings I've had 2 IS300's and a LS400 so far and I have unlimited use of a buddy's spare SC400 that's been parked in my driveway for a few months.
I've also had 3 TT Mk4 Supras, 6 Mk3 Turbo and 4 Mk3 NA Supras, 2 "P-Type" and 1 "L-Type" Mk2 Celica-Supras, and 2 Mk1 Celica-Supras over the years and my first car was an old used carbureted Mk1 style Celica GT Liftback with well over 100k miles on it when I got it and a whopping 96 factory horsepower at the crank, not at the wheels, which I still think was one of the most fun cars I've ever had...

So how much power can a totally stock VVT-i 2JZ-GE actually tolerate and how much power with the NA manual or automatic tolerate before something expensive breaks? When I had my first IS300 (I've had 2 so far) they were still available new and people with 400-500 HP typically had totally "built" the motor and put a Mk3 Turbo Supra's manual transmission in it because they kept blowing things up with the stock IS300 VVT-i engine and/or transmission.
Wow, you've had a very nice collection of cars!

I honestly can't say how much a stock VVTi 2JZ-GE or AT/MT transmissions can handle before something blows up. From what I've read online, it seems like the stock platform can tolerate up to 350whp, however that could still be pushing it. When my buddy had his NA-T setup with stock everything, I believe he made around 260whp-ish on the dyno. He did as you said most do and later swapped in a 2JZ-GTE engine with a TT 6spd. You're totally right though with the power to weight ratio... 300hp in a 3300ish pound car would make anyone new to that power level feel like they're in a rocket.
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post #18 of 18 (permalink) Old 04-20-2018, 08:24 PM
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Originally Posted by FRaCTioNaL View Post
Hahahahaha. The abysmal fuel economy is why I have a dd and never used the damn thing. It mostly sits in pieces in the garage. Gotta understand though, they are so cheap nowadays that it's a kids market. Welcome to the new forums :s
Sitting in pieces? Is it a never ending mod project or the fun of turning wrenches or is it actually broken?
The abysmal fuel economy of most Lexus' is pretty much the only reason I haven't had one as my daily driver in a long while. I'm not an eco warrior or carbon footprint fanatic but I could get 24-27mpg cruising down the interstate with the AC on in my 450 HP TT Mk4 Supra as long as I didn't speed too much and/or play too much along the way and yet my 200 HP NA IS300 and my buddy's wife's SC300 typically got upper teens on the highway and had to be driven gingerly to get low 20's. What's wrong with this picture... At least in the SC400 and LS400 you've actually got lots of torque and some real mid range and top end power and the fun of the V8 while getting the same abysmal freeway fuel economy as the NA I6 2JZ-GE. I seriously thought about getting a CT200h because at least it has the L badge but I reeeeally don't want to own a Prius, especially after having driven one recently for the first time and already knowing that my 90hp TDI is actually just a little faster which I learned when a buddy's wife wanted to race her Prius against my TDI a few times and it was like watching grass grow although my gobs of low torque and major turbo spool from a stop by slipping the clutch on the manual transmission always put me half a fender or more ahead from the start and usually kept me slowly walking her more and more although we'd have to get to illegal speeds for me to fully take the lead and her economy was technically higher but I can go twice as far or more per fill-up with my much larger fuel tank...

Originally Posted by toneekay View Post
Wow, you've had a very nice collection of cars!

I honestly can't say how much a stock VVTi 2JZ-GE or AT/MT transmissions can handle before something blows up. From what I've read online, it seems like the stock platform can tolerate up to 350whp, however that could still be pushing it. When my buddy had his NA-T setup with stock everything, I believe he made around 260whp-ish on the dyno. He did as you said most do and later swapped in a 2JZ-GTE engine with a TT 6spd. You're totally right though with the power to weight ratio... 300hp in a 3300ish pound car would make anyone new to that power level feel like they're in a rocket.
Pardon the "novel" and the occasional wandering of thoughts along the way but hopefully it's a worthy read as I actually attempt to provide some real world feedback, comparisons, thoughs and opinions...

Thanks for the info and thanks for the compliments too!
I've definitely been fortunate over the years to have slowly worked my way up from a Mk1 style Celica one by one through the Supra generations and types to a Mk4 TT Supra with the IS300 and LS400 and a boring mid 90's Camry in the mix along the way and it was always fun getting to experience and compare each one to the next. They literally kept getting even faster and even nicer until the Mk4 which came with amazing power and handling but abysmal interior quality and features but it's still a fun car in its' own very obvious ways. The one exception that I've never owned is an NA Mk4 Supra for several reasons. They've been insanely over-priced since that first movie came out. I daily drove an NA Mk3 for over a decade with several Turbo Mk3's and a TT Mk4 in the mix as the play-toys so I know how slow the NA Mk4 is and how mediocre the Mk4 interior is so all you're really getting is the looks for that price. Plus I know how limited their mods path is and I know what those mods cost and I know what gains they achieve and for the money you can just buy a TT and BPU it for comparable or less money unless you find a running salvage title NA dirt cheap. I decided that if I'm going to own a car that slow it's going to be an IS300 which is newer, smaller, lighter, has a better quality interior, and is more nicely equipped for a whole lot less money although like the 96-98 NA Supras the IS300 is even harder to mod than the 93-95 NA Supra.

Wow, kids' market. I forgot about that... The last time I went through that was with my Mk3 Supras. They were still nice and still expensive and still fairly new used cars when I got my first one but many years later while I was still driving my first one and had bought a second one to play with they had just started to become a used car target of the first generation fast and furious wannabe's who couldn't even dream of affording the "real" (2JZ) Supras at all. It was frustrating watching them buy cheap parts and cut corners and burn valves and roast pistons and end up with rod knock and then start trash talking the car because of their chasing big power with clueless stupidity when it's totally possible to get a 7M-GTE powered Mk3 to rival a BPU TT Mk4 as a reliable daily driver if you use good quality parts and buy all the necessary parts for the upgrade and realize the requirements of the build level you're shooting for and understand why skipping any of the proper steps for that performance level might make it fast for a minute or a month or two before it blows up. There's a Mk3 parked in my driveway with 550cc injectors (the stock US Mk4 TT injector size vs the 440cc Turbo Mk3 stock size) and a 57-trim upgraded factory Mk3 turbo that could and often did easily hang with and usually would slightly walk away from my 450 WHP TT 6-Speed Mk4 with both cars at WOT up to about 130mph when the Mk4 would reel it in and walk away as the Mk3 started running out of top end power and gearing. That Mk3 got its' BPU mods done many years earlier at just over 100k miles and was its' previous owner's daily driver for well over a decade and it now has over 200k miles on it and finally wants a new head gasket which is why that owner decided to let it become mine recently and knowing what that Mk3 will go back to doing reliably again for a long time as-is once I take a weekend to replace the leaky head gasket and flush the fluids and double check a few things is exactly why I wanted it.

I suppose that's part of why I find it almost annoying when someone says "I'm just looking for something to make my daily driver car fun but keep it reliable, like maybe 400-500 HP?", especially when they're starting out with a 200hp-ish car like the IS300 and think it's capable of 3-4 times the stock power level just because it's a 2JZ family of engine like the 2JZ-GTE that's in the Mk4 TT Supra.
You couldn't even take a OBD-II NA Supra and bolt on a turbo and boost it reliably to that kind of power, it had to be the OBD-I motors which pre-dated VVT-i and even then there were a lot of things you had to do to the car to get it to handle a turbo.
I watched several people buy 93-95 NA Mk4 Supras and try doing a turbo upgrade and time and time again my TT 6-Speed and TT Automatic with just intercooler, exhaust, and boost controller would usually put down significantly better power and torque numbers with my boost controller still turned off (the twins typically made 10-12psi on their own) than their boosted NA car would do on the same dyno with their tuning work and boost controller as high as they could push it and then their feelings would get hurt when I turned on my boost controller to a reasonable mid range street level of like 15-16psi on my stock twins which only got worse when I let it do the full 18psi. One of them got frustrated after several attempts and cranked everything to the max and finally got it pretty close to what my BPU TT Auto was making with no boost controller on the same dyno but it took him twice the boost to get that close and my car was far more daily driver friendly because his turbo lag was totally nuts. Don't get me wrong, they were still putting down considerably more than a US TT 2JZ's stock crank HP numbers to the NA car's wheels which is a huge power increase and their cars were still fun play toys for sure but the reliability was iffy at best and their power control was really unpredictable for use as a street car and the NA brakes and suspension and transmission weren't set up for that kind of power and by the time you do everything that should be done and do it properly, even doing all the work yourself you could've bought a TT instead and your VIN still says it's an NA chassis so your insurance coverage won't be anywhere near enough if anything bad ever happens to it and if you try to sell it you almost always have to settle for less than if it were an actual TT VIN which is usually far less than you've put into it.
The cost difference between the Auto and 6-Speed was typically around the cost of the 6-Speed transmission itself and the cost of swapping out the auto would usually exceed the difference in car prices although it was generally $5k-$10k more for an original 6-Speed car depending on condition and mods.
The 6-Speeds are definitely a lot of fun but I've had 2 auto's, left one totally stock, and thoroughly enjoyed driving all 3 cars.

So it seems like 250-300 HP at the wheels sounds like a reasonable mod level to retain the reliability of the IS300 without having to get into actually building up the engine although the transmission may or may not get unhappy along the way without some prep work and that power level won't blow the doors off of a muscle car but if you can't find any fun in a 300 hp IS as a daily driver then you need a lot of money and/or a different car because I can tell you that a well set up 250-350 whp car with proper brakes and decent suspension and tires on the streets is a whole lot of fun. I had a 160 hp (crank) Mk2 P-Type 5-Speed Supra (Toyota's first gen IRS and first gen Twin-DOHC) that I owned from 2006-2014, my 2nd P-Type and 3rd Mk2, that was almost as old as some of my car group friends and everyone who I let drive it, no matter what age they were, just couldn't stop smiling from the moment they dumped the clutch and it eagerly kicked the rear end out to the side and spun the stock 14x7" tires through first and second gear... From 0-35mph The P-Type Supra was geared from the factory to be downright quick even by today's standards, oh and it was still totally reliable with 100% working power everything including automatic climate control and on top of all that it actually weighed about the same as an IS300. So much fun with nowhere 500 HP.

But I suppose my definition of a fun car isn't all about trying to be the fastest and the most furious, it's more about what makes me smile and an agile car with decent power and lots of creature comforts usually does that for me regardless of what anyone else thinks because there's always going to be someone else with more money than sense with something newer, bigger, better faster, and if there isn't at this very moment there's a really good chance that there will be tomorrow and for me it's all about having fun with cars, not about bigger badder bragging rights.

The best way to find out what a good path would be is to experience a car that's already done it and see what you think. A 2JZ isn't some magic power monster that pukes endless power with a turbo. Neither is a 1JZ. Each has its' pro's and con's and limitations, especially when you're looking for a balance of power and reliability from either of them without taking them apart for internal upgrade work first.
Even the Mk4 Supra's 2JZ-GTE can start smoking and showing signs of unhappiness in a 500-700 hp stock TT motor after a fairly short while if you bolt on a big single and/or spray it with NOS and actually push it to perform at that power level on a regular basis, especially as a daily driver. You "can" do enough of the right mods to get that GTE to make 1,000 WHP without cracking open the motor but it's not going to perform like that and still hold up for years as a reliable engine and the stock auto sure as heck will not last. I've had a stock TT auto start noticeably slipping between shifts under boost with less than 400 whp if I didn't back off from WOT when it was time for it to shift. I've also had a 6-Speed with a TRD clutch upgrade start slipping after 25,000 miles at just 400 whp. I replaced it with a lightweight flywheel and carbon twin-disc clutch setup while a buddy with 600 WHP went with the considerably cheaper single-disc setup from the same clutch company and when he decided to get a bigger turbo his fairly new clutch that had already cost him well over $1,000 had to be replaced because it started slipping within a week of his power upgrade so he ended up with the more expensive $2,000 clutch setup I had chosen for my car which I chose because I wanted the ability to beat on it hard at my BPU power level without worrying about clutch problems plus I wanted the capacity to go for big power in the future without needing a new clutch again.

As for the 1JZ-GTE, although they're far more common these days and there's a lot more aftermarket support around today than there was when a buddy was considering getting one for his Turbo Mk3 in 2001 you really have to consider the fact that we never got that engine in the US market and many of them are close to 3 decades old now as I think the JDM Turbo Mk3 Supra and other models got it as far back as the 1989 model year so it's not like you can walk into your local Toyota dealer, much less Auto Zone, Pep Boys, NAPA, etc when you need parts for it, especially if it's your daily driver car.
So it seems like that's something else to really consider when you're talking about dropping a potentially 30 year old used turbo motor into your 2001-2005 reliable daily driver IS300 Lexus.

I've thought about looking into a turbo kit for the running and driving 1UZ-FE SC400 in need of some tlc that a buddy has basically given up on and left in my driveway but the power gains vs cost that I've read about so far has held me back.
I've also thought about a 2JZ-GTE swap as unlike the IS300 where I've read that you have to go single with the 2JZ-GTE because of space issues I'm pretty sure that the stock twins will actually fit into a SC chassis and I still have plenty of spare TT Supra BPU parts and the 2JZ-GTE's keep getting cheaper year after year but apparently it's a bit more involved swap with the SC400 chassis than the SC300 chassis and so far the roughly 400HP Turbo Mk3 Supra with the bad head gasket that looks so much more unique and retro cool these days seems far more appealing to me but time will tell...
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